After my sons graduated and left home, my husband and I adjusted. It wasn't hard. Yes, we fondly recalled folding dryer-warmed T-shirts commemorating rock concerts and seeing our sons' stubbly faces as they stumbled out of bed after a hard night. But it was pretty damn roomy, that nest… until it wasn't empty any more.

When we learned that, at 25, one son would be returning to live with us again, we expected his stay to last perhaps two months. The next month, he lost his job. After a few weeks, my husband and I found ourselves unable to zip our lips. Have you updated your CV? Looked online? While you're at it, could you please do your laundry? Clean up? Walk the dog?

Months passed. Our son mentioned that he'd been offered a position, though the job sounded dull – and what was the rush to work again? Within his crowd, joblessness seemed to present no stigma and, given that he had few financial responsibilities, he was managing well, thank you very much. That's when my husband and I staged an intervention and, with a shove, our son accepted the job and moved out.

A decade on, the number of adultescents living in their parents' homes looks like nothing less than a stampede of chicks coming home to roost, victims of a flatlined economy. According to the Office for National Statistics, nearly three million British adults aged 20-34 lived with their parents in 2011, up 20% since 1997. More than one million under-25s are now unemployed, and with the introduction of higher tuition fees, future students should expect to finish their degree with debts approaching £60,000, according to a survey published by the independent student guide Push. Lending institutions are shying away from offering mortgages and house prices have risen beyond the realms of possibility for many young people, who are often poorly paid if they actually work, or find that an unpaid internship has become the new entry-level job.

These experiences may result in a severe hit to self-esteem; returning home to loving parents can sometimes soothe that wound. Many young adults, however, exist in a cloud of overconfidence, with an illusion of endless time. "This is a more entitled generation than their parents' and grandparents'," says William J Doherty, professor of family social science. "We're seeing young adults tethered to family in the sense that they live at home, but with no major responsibility to work as contributing members."

Today's parents are likelier to treat young adults like pampered teens, reinvesting in dormant parenting roles, especially if their kids are floundering. "The subliminal message that comes with all the giving and doing is, 'We don't think you can do it on your own,'" says Marie Hartwell-Walker, psychologist and mother of four adult children, two of whom came home to live with her and her husband.

It's painful to recognise that biology's imperative is for younger generations to manage without parents, and that many life lessons must be learned alone. This truth is compounded by baby boomers' outrage at the very idea that they have to age, which sends an additional, if subliminal, message to young adults that there will always be time to get another degree, to break up with one more partner or employer, picking a direction, reversing it, spinning the dial again. If parents aren't "old" – and with hair colour and joint replacements, who doesn't want to pretend they're still 40? – then for adultescents, the years must be standing still. Parents of adult children need to step back so young adults can step forward. It's never too late for kids to grow up.

Gareth Johnson, 38, lives with his parents, Carl and Eunice, and his nephew, Seth, 12, in Norbury, south London

Gareth says: Apart from a year studying in Dundee and a few spells abroad last year, I've lived at home all my life. My mum and dad are ridiculously supportive. They've never broached the subject of me leaving. I'm unemployed – I got an MSc in forensic art a few years ago, but haven't found work in that area yet. I've applied for more than 300 jobs.

Everything changed when my sister died suddenly six years ago. She was living at home, too, with her son, who is now 12. I had been umming and ahhing about moving out and that put a hold on things. It changed my whole perspective on life. I used to work in TV production design, and it made me want to do something more worthwhile, which is why I did my postgraduate degree.

Mum and Dad are raising my nephew, Seth; I'm a sort of dad/uncle/brother rolled into one. They give him a really stable background, just like they did for me. You couldn't wish for better parents. I'm the fun element. Would I still be at home if it weren't for Seth? I don't know, but he doesn't keep me here. I'd prefer to get a job and my own place, and I'm sure Mum and Dad want me to as well.

I sign on, so I don't pay any rent. After paying off my creative development loan, there's nothing left. We lead quite separate lives. I'm more of a night person: I go to bed around 3am and get up about midday. We eat together most evenings, but cooking is a bit contentious: my mum and dad don't eat the sort of stuff I like, so they tend to do the cooking. Dad does most of the cleaning, but I do my own laundry and clean up after dinner.

Mum nags me, of course, about shaving stubble on the sink, leaving my beer-brewing tools around, hoarding towels. I think they've accepted that's what I'm like. I don't get any stick from mates – they've all done the back-to-home thing at some point. A lot are aspirational in what they want to do with their careers, like me. I love living at home because of the security and it's great seeing Seth grow up. But I hope I leave before him.

Carl says: When Gareth came back from Dundee, we all expected him to start on a new career and move out. He's been back nearly two years and it hasn't happened yet. We share his frustrations and disappointments – it's a difficult climate. We're supporting him in the best way we can. If we had the money to set him up on his own, we would. Some of our family think we're a bit too supportive and drop hints that Gareth might try to find a job. But we don't charge him rent because he can't afford to pay it – he's trying to pay off his loan.

We do like having him around. He's handy round the house and although he has what you might call a limited repertoire of meals, he's brilliant at clearing away. Like any family member, he has good and bad points: he's always leaving the lights on, but he brews fabulous beer. He and Seth get on famously: they play football in the hall, just like Gareth did as a kid with his own uncles.

After losing our daughter, Lisa, Gareth has become more precious to us. But we have an adult relationship with him now, not a parent/child one. He's still our son, and we love him to bits, but he's also an adult.

Michelle Nicoll, 27, and her husband David, 30, have been living with her parents, Jan and Keith Rutland, in Hatfield Heath, Essex, for 17 months

‘It feels as if our lives are on hold,’ says Michelle Nicoll, with husband David and parents Keith and Jan. Photograph: Lucy Levene

Michelle says: David and I had been renting for two years before we got engaged and realised we'd never be able to afford a wedding and a deposit for a house while wasting money on rent. We had no savings and though we didn't want a big wedding, we wanted all the family there. Our only option, as we saw it, was to move back in with my parents. Some people think we're mad, but I've always wanted marriage, a house and kids, in that order.

My parents had always said we'd be welcome, and we'd joked about it, but it was depressing – I felt as if we were imposing, and that we'd failed. We'd started out as an independent couple, with our own routines and our freedom, and had gone backwards. We got married in May, but it feels as if our lives are on hold.

The hardest thing is doing everything to my parents' routines. When we lived together, we did chores as and when we felt like it. Now we feel we have to wash up straight after dinner, or tidy up when they want us to. They don't go out a lot, so we have no time alone at home. We have a little area upstairs that we use, but it's so cramped with furniture, and our two cats, that it's hard to relax.

Between us, David and I pay £225 a month in rent, which probably doesn't even cover food or electricity. My parents want us out sooner rather than later, and I'm sure they know if they charged us more, it would take us longer to save up for our deposit. We save about £1,000 a month, and we've wiped out our bank loans and credit card debts.

We had quite a bit of furniture, as we were renting a two-bedroom house. Some of it is in the garage, and the loft, and we bought a shed. We planned to be here for a year to 18 months, but I think we'll be here another six or seven months.

Jan says: We knew Michelle and David were in a bit of a mess and needed to save up for a deposit. We thought, if we don't help them out, there's no chance of them getting anywhere. We'd had a few years enjoying not having children at home, and spreading out, so it was hard condensing our stuff again. Michelle and I are very different and we have clashed, particularly in the kitchen. She likes things done properly, whereas I'm quite slapdash. They have two cats and it took our dog a while to get used to them. And we had to work out timings for the bathroom in the morning, as we've only one. It has been quite fraught on both sides.

For their sake, mostly, I'm looking forward to when they move out and can get their lives in order. I'll miss them, but I'm looking forward to having our own space back. We're going to have people to stay again – we knocked that on the head when Michelle moved back in.

David Gardener, 35, has lived with his parents, Sue and Dennis, in Perth for the past 16 months

David says: I was living with a girlfriend in Glasgow and we split up; I had nowhere else to go. I don't have a job at the moment. I'd always worked in the hospitality industry – as a chef, and doing restaurant and bar work – but decided to do a degree when I was 26, then a master's. I'd ideally like a job in social research or social policy, and must have applied for nearly 1,000 now. I'm even looking for catering work again, and I'm doing voluntary work for a local wildlife charity, which gets me out of the house.

The biggest adjustment has been working round their routines, so I find it easier to do my own thing. They have an extension where I camp out and watch American dramas such as CSI, and sport. Mum tends to watch stuff like Poirot. I've tried to keep as much independence as I can: I do my own laundry, clean my own room, and help out as much as I can, mowing the lawn, hanging curtains. They're away this weekend, so I'm doing some painting and decorating as a thank you. They don't nag – they know I'm doing all I can to find a job, even if they don't understand the line of work.

It's hard to meet women around here, mainly because I don't have many friends in Perth so I don't go out much. I have had a relationship since living here, but she was in Edinburgh and it didn't work out. I don't mind living here – I'm used to it now and do have a lot of freedom – but I haven't any other option. As soon as I get a job, I'll be off.

Sue says: We had a call saying, "Help, I haven't told you but I'd moved in with this girl and she's thrown me out." He really didn't have any choice but to come and live with us. It's been a shock, as he's always worked. Even if he didn't like a job, he'd always find another one first before moving on. A few weeks ago, things were looking promising with one application, but apparently there were people with PhDs ahead of him in the queue.

I really like having him at home – I haven't seen that much of him over the years. He's had one relationship since living here, but it didn't last. She lived in Edinburgh – his dad would never tolerate a girl staying the night, and he couldn't afford to go and see her all the time. I'd love him to meet someone but at the moment it's a no-no. I think he's a bit isolated here, but I'd never turf him out. He's my son, I'd do anything for him. Interviews by Hannah Booth